This invention relates to a method and system for passive vehicle entry that automatically locks and unlocks a vehicle port.
Many vehicles employ remote entry systems that permit a vehicle operator to lock and unlock the doors and trunk of the vehicle. Such systems usually comprise a transmitter located in a key device, say a key fob, and a receiver located in the vehicle. Upon activation by the driver, the key device fob transmits a key code to the receiver. A control unit then compares the key code to a security code to determine whether the key code matches the security code. In the event of a match, the control unit locks or unlocks the vehicle.
Such systems require the driver to manually activate the transmitter, providing less convenience of operation. When the driver""s hands are occupied, such as when carrying bags, the driver must free his hands to lock and unlock the vehicle. This limitation is undesirable.
Passive systems do exist that permit the driver to lock and unlock the vehicle without activating the transmitter within a key fob. Such systems use capacity sensors located in a car""s door handle that communicate with a control unit in the car. When the control unit senses the presence of the hand lifting the handle, the control unit sends a challenge to a key device carried by the individual to determine whether the individual is authorized to unlock the door. The key device responds to the challenge by transmitting a key code. The control unit determines whether the key code is, in fact, the correct code. If so, the control unit unlocks the vehicle automatically.
Current capacitive systems essentially work as touch sensors. As a consequence, the vehicle security system has very limited time to respond to the touch of the operator and unlock the vehicle port, say car door. Sometimes the operator may touch and lift the handle so quickly that the system will have not authorized entry prior to the handle hitting the end of its path of travel. In such an instance, the authorized operator will have tugged the handle without automatic actuation of the vehicle lock.
A need therefore exists for a passive entry system that provides greater advanced notice to the vehicle security system of the operator""s intention to unlock the vehicle door.
The invention comprises a port control system that employs a capaciflective sensor to detect the presence of objects at a greater range than current capacitance sensors. Such sensors provide improved advanced notice to vehicle security systems of the approach of a vehicle operator toward a vehicle door or trunk, thereby permitting the security system to check the operator for entry authorization even prior to touching the door or trunk latch. Thus, the current system is transparent to the operator, who may seamlessly and smoothly open the vehicle port without any delay caused by security clearance.
The vehicle port control system comprises a capaciflective sensor, a lock securing a port such as a door or trunk, and a control unit. The capaciflective sensor is set to sense for objects, such a human hand, at a predetermined distance from the door or trunk. Such sensors may be set to detect for the presence of objects from six to eight centimeters from the vehicle latch, significantly improving on the range of current sensors. The system may also include an electronic key device, such as a key fob.
Once an object is detected within the range of the capaciflective sensor, the control unit determines whether the operator is authorized for entry. If so, the control unit actuates the lock. The control unit may determine authorization by requesting a key code from the key fob. In response to this challenge, the key fob then transmits this code to the control unit, which then compares the key code to an unlocking code. If there is a match, the control unit unlocks the lock. The request for the key code may occur when the object is sensed within the range of the sensor.
The invention may also be combined with other vehicle subsystems such as a power vehicle seat system, the vehicle sound system, or air conditioning system. The control unit may then set these systems to the personal setting of the particular operator.
To avoid actuating any lock before the operator truly intends to open the vehicle port, the system may also be combined with a latch sensor. Movement of the latch signifies to the control unit that it should unlock the vehicle port. Prior to this actuation by the operator, the system remains on standby with authorization already cleared. The latch sensor may be an infrared sensor.
The system may also be set to xe2x80x9ctune outxe2x80x9d rain, snow, and other environmental conditions that may otherwise trigger the invention to commence searching for proper authorization. The system accomplishes this task by comparing the signal from the capaciflective sensor with a predetermined threshold. This threshold may be attuned to trigger the search for authorization upon detection of a person or a portion of the person within the range of the capaciflective sensor.